<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>05_面试题</title>
  <link rel="stylesheet" href="xxx.css">
  <style>

  </style>
</head>
<body>
<div style=""></div>
<script type="text/javascript">

  /*
   测试题1:  先执行变量提升, 再执行函数提升
   */
  function a() {}
  var a
  console.log(typeof a) // 'function'


  /*
   测试题2:
   */
  if (!(b in window)) {
    var b = 1
  }
  console.log(b) // undefined

  /*
   测试题3:
   */
  var c = 1
  function c(c) {
    console.log(c)
    var c = 3
  }
  c(2) // 报错

</script>
</body>
</html>